1. Field of the Invention
The present invention relates generally to the oil industry, particularly reservoir engineering, and more particularly to systems, program product, and methods for providing real-time reservoir management of one or more oil reservoirs across one or more oilfields.
2. Description of Related Art
Various types of recovery methodologies are used to recover crude oil or other hydrocarbons. A primary methodology for recovering oil, for example, includes use of natural underground pressure, which can originate from several sources including an underlying water layer below the oil layer or a gas cap formed of gas collected immediately above the oil layer. Whether or not such underground pressure initially existed, once reservoir pressure has either been depleted or is otherwise below a minimum value, oil must be brought to the surface using secondary methodologies. One of the secondary methodologies includes injecting water below the oil layer. Another methodology includes injecting a gas above the oil layer. Other methodologies of extracting oil, particularly when underground pressure has been depleted to a point where the reservoir cannot be sufficiently pressurize, can include reducing the viscosity through the injection of heat, vapor, surfactants, solvents, or miscible gases (e.g., carbon dioxide). Efficient reservoir management may dictate maintaining underground pressure using one of the above methodologies, rather than allowing reservoir pressure to be depleted.
Water is a particularly useful tool in reservoir management in that it can be used to, not only pressurize a virgin or depleted reservoir (both naturally or through injection), but can also be used to proactively maintain reservoir pressure and/or to direct oil in a reservoir toward an existing oil well. Various reservoir/field characteristics that may lead to a requirement to use water injection can include, for example, the existence of tight flank permeability or the existence of a non-permeable tar mat. Tight flank permeability can prevent enough aquifer support from reaching the crest area of the field.
Various methodologies including, for example, the use of long reach flank injectors with multi-kilometer reservoir exposure can provide adequate injection rates to support the producing area of the affected reservoir. The presence of a non-permeable tar mat across the flanks of the field, however, can prevent aquifer support from reaching the producing area. Various methodologies including, for example, drilling or reactivating up-dip injectors placed above the tar-oil contact layer can provide for adequate injection rates to support the producing area. In order to determine such location, a data-gathering project may be employed to properly map the tar mat. With knowledge of the structure of the non-permeable tar mat, the water can be injected using high pressure, high flow rate pumps, which can each include a wellhead pressure water sensor and flow rate meter. Water injection, however, is a progressive process which includes a substantial lag time between injection of the water and a pressure increase or oil migration in the vicinity of a targeted section of the reservoir or a specific well or wells.
As such, it can be readily understood that, until now, substantial challenges have prevented efficient reservoir management through water injection, particularly when there exists a significantly large non-permeable tar mat and/or tight flank permeability. For example, reservoir engineers, using conventional technology and methods, have been challenged with trying to understand reservoir performance based on a few static pressure surveys conducted across key wells, annually or biannually. Such lack of continuous data lowers or minimizes their understanding of important reservoir performance messages and may result in missing significant production injection optimization opportunities. Producing operators, using conventional technology and methods in order to try to meet reservoir engineering pressure survey requirements, for example, are challenged with the difficulties associated with having to shut-in each key well one day before the survey and at least one day during the survey, which results in a loss of production or injection, and are challenged with the difficulties of a shut-in time beyond one week beforehand for wells in tight reservoirs, in order to obtain a representative static reservoir pressure value. Producing operators are also challenged with providing the required logistics to perform the required annual/biannual surveys including manpower and survey equipment, e.g., wireline truck, pressure gauges, etc.
Accordingly, recognized by the inventors is the need for systems, program product, and methods of providing real-time reservoir management of multiple reservoirs across one or more fields: that can provide continuous data that allows reservoir engineers to maximize their understanding of important reservoir performance messages and to identify production injection optimization opportunities; that can negate a need for shutting down a well in order to obtain representative static reservoir (e.g., bottom hole) pressure values, allowing for substantially continuous producing operations; and that does not require the performance of annual/biannual wireline surveys or the associated logistics, e.g., manpower and survey equipment including a wireline truck, pressure gauges, etc., needed to perform such annual/biannual wireline surveys.
Additionally, various reservoirs can have different crude grades potentially resulting in a need to adjust production across the different reservoirs in order to obtain a required or desired crude blend. To overcome such challenge, the inventors have recognized the need for real-time data including, rate, pressure and temperature, collected across the entire network, from reservoir to central producing facility, and matched, for example, using an integrated model for more efficient, real-time reservoir reservoir pressure estimations and enhanced real-time reservoir management.